MH the other thing to look at once booted in Safe Mode is in the win.ini file (run sysedit.exe) and look at the load= and run= lines. If there are programs listed there, make a note of them and erase them, leaving load= and run= empty.
Another thing to look at is the startup programs set to load in the registry. Use regedit to inspect this. I can't remember off the top of my head where they are located in the registry, but should be somewhere in HKEY_LOCAL_MACHINE.
If you do need to do a reinstall, I would suggest giving it to your son as a project, seeing as he broke it